The present invention relates to an electroconductive composition, an electroconductive film-producing method, and an electroconductive film produced thereby.
Various methods have been used in producing a circuit board. In one known method, an electroconductive composition is printed on a synthetic resin substrate such as a polyester film, for example, by screen printing to thereby form a predetermined circuit pattern, and an electroconductive film constituting the electroconductive circuit is formed by heat treating the printed circuit pattern. The electroconductive composition used in this method is, for example, a silver paste produced by adding a binder made of a thermoplastic resin such as acrylic resin or vinyl acetate resin or a thermosetting resin such as epoxy resin or unsaturated polyester resin, an organic solvent, a curing agent, a catalyst, and the like to electroconductive particles such as silver particles, and kneading the mixture to prepare the silver paste.
For example, JP 07-331125 A discloses “an electroconductive paste comprising 100 parts by weight of an electroconductive powder containing a powder of a copper alloy which is represented by the general formula AgxCuy (0.001≦x≦0.4, 0.6≦y≦0.999 (atomic ratio)) and in which the silver concentration on the surface of the particles is higher than the average silver concentration of the particles, the average particle diameter is in the range of 1 to 10 μm, and the fine particles having a particle size of 0.1 to 1 μm account for 5 to 80% by weight of all particles; and 10 to 40 parts by weight of a binder resin containing a thermosetting phenol resin having a weight average molecular weight of 300 to 4000 and a molar ratio of formaldehyde/phenol of 0.8 to 2”.
JP 09-92029 A discloses “an electroconductive paste which uses an electroconductive metal powder and an epoxy resin which serves as a binder for the metal powder”.
JP 2003-203522 A discloses “a silver compound paste containing silver oxide particles and a tertiary aliphatic acid silver salt”.